Continuing the thread from my last post, let's discuss what will cost you serious 'currency' in the marriage marketplace and what will not. Readers should be warned that there is some reductionism here as well as more than the usual dose of candor.
Whether this constitutes something akin to value investing depends greatly on what you, the reader, actually value (actually value, not say for public consumption that you value). Since we're writing primarily for the benefit of the non-neurotypical male, we'll look at the marketplace from that perspective. Readers with other perspectives will need to translate accordingly.
By far and away the most 'expensive' thing is her looks---as in, the approximate percentile where she falls relative to women her age when viewed from a male perspective. This is what will cost you dearly. The only thing even close to as pricey as this is her age relative to yours. If you know these 2 things, you know probably 90% of her value in the marriage marketplace viewed by the average male participant.
The good thing for you is that if you followed my advice in previous posts, you've accepted enough first dates that you now have a pretty good idea just how desireable you are in the marketplace yourself. My personal observation is that, when dealing with marriage-minded women (i.e., women who are consciously aware that they're in the marriage marketplace and not merely the sexual marketplace), women who are of similar marketplace value to you will actually tend to react the most favorably towards you. It's actually NOT the women who are lower on that hierarchy than you that will usually do so---they'll avoid investing too much if they see you as nearly unobtainable. Note also that the mere fact that you're 'interviewing' lots of applicants will improve your status in the whole process, and it'll probably also protect you from becoming overly committed too early.
Here are some things that will cost you a little---they're not free in the marriage marketplace but you might be interested in them.
Her grace in movement: The classic example is the woman who did ballet when she was younger and probably still enjoys dance, yoga, or similar pursuits now. This does command a bit of a premium in the marketplace.
Particular hair/eye/skin coloration combinations that some, but nowhere near all, guys have a minor fetish for: e.g., blue eyes/blond hair, fair skin or red hair/green or blue eyes/fair skin with a few freckles
How pleasant and agreeable her disposition in general is and her overall level of mental stability: This, IMO, is seriously undervalued. I give it a strong buy regardless of who you are.
Here are some things that cost almost nothing---this is to say, a woman with them experiences only a trivial increase to her average value in the marriage market
Intelligence: In general she ought to be within 2 sigmas of you, and most women prefer that you be the smarter one. But in itself this doesn't make her any more marketable, although it may make her harder to find.
Artistic ability: Only will cost you much if its pretty seriously out there--e..g. 3-4 sigma ability in singing
Cooking and other domestic ability: Again, only costs you if its seriously out there, and even then, not much
Height: Won't cost you much at all---it doesn't seem to matter much for women unless they aspire to be models. This isn't true of guys, who seem to get the maximum bonus around 6' to 6'2"--tall enough to be noticeably taller than the average, but not to trigger any uneasiness
Athletic ability: Again, this costs you almost nothing (although any woman who has a significant amount of it nearly guarantees herself around 60th-70th percentile in looks by the simple expedient of NOT being significantly overweight). This also isn't true of guys, who actually do get fairly significant mileage out of being visibly athletic.
Quality of her family, especially her parents: This costs you almost nothing, most guys aren't even smart enough to consider it early on. If her relationship with her father is solid, and her mother is married to her father still and treats him with consistent respect, this is a VERY good sign, and one that the marketplace IMO seriously undervalues. STRONG BUY once again
Level of Religious Commitment: Unless she's an Amish or the like, this costs you almost nothing. As before, I've advised readers that generally only women who have strong, credible, and expensive signals of piety are good risks in the present marriage environment. The good news is that the marketplace hasn't caught up to that recommendation (IMO, that reality) yet, so you won't need to pay much for it.
Non-neurotypical tolerance: I'm guessing you want this quite a bit also. You're in luck, it's practically free. Being an 'engineer's daughter' like my wife doesn't tend to make you significantly more or less desired by the average man, but for you, gentle reader, such a woman is likely to be a much better fit.
Some people like to say that a house is likely to be the most highest stakes negotiation you'll ever be involved in---I disagree, I think selecting your mate is by far.